New South Wales 258 for 8 (Patterson 86, Morris 4-25) lead Western Australia 196 by 62 runs

After 13 wickets fell on the opening day, the match appeared to be moving at warp speed in echoes of last month's remarkable WA-South Australia clash at the WACA - the shortest outright result in Shield history.

NSW teetered at 26 for 4 in reply to WA's first innings of 196 before No. 3 Patterson, who was dropped twice, rescued the innings with unwavering powers of concentration to make 86 from 262 balls. He survived an onslaught late on the opening day before defying WA's strong attack until he finally fell to Morris in the final hour of play.

Patterson departed short of a deserved century, but continued his outstanding Shield season where he has now tallied 697 runs at 69.70. Patterson had an intriguing battle with Morris, who straddled sharp pace and control to good effect and finished with 4 for 25 from 18 overs.

Morris, playing a rare back-to-back Shield match, does have a restriction of around 30 overs per game coming off a stress fracture last winter as well as a quad strain late in the pre-season. "I think I'm going to be a little bit restricted [bowling for the rest of NSW's first innings], need to keep a few [overs] up the sleeve if we want to try and chase a result," Morris said after play.

Just 0.24 points separated second-placed NSW and WA before this round began with a victory for either team putting them in pole position to reach the final.

Resuming at 17 for 3, NSW were initially in a battle for survival on day two but WA were left to rue an early chance off Patterson when Sam Fanning dropped a tough catch at short leg.

Nighwatchman Liam Hatcher, the second used in the innings, succumbed quickly when he was late on a short delivery and miscued to quick Cameron Gannon, who dived forward to take a sharp return catch in his follow through.

Having claimed two wickets during a fiery spell late on the first evening, Morris bowled angrily after the earlier missed chance off his bowling. He consistently bowled around 140kph and bent his back to ensure the ball sizzled past the helmets.

Matthew Gilkes unwisely took his eyes off the ball on one particularly fierce short delivery from Morris and copped a blow to the grill. He was shaken but stuck it out and provided good support for Patterson, who dropped anchor and scored just eight runs off his first 50 deliveries.

After such a torrid time against pace bowling, his eyes lit up when offspinner Corey Rocchiccioli came into the attack and he swept superbly to finally get the WACA's legendary scoreboard ticking over.

But Patterson had more fortune on 27 when Fanning dropped another tough chance at short leg much to the despair of Rocchiccioli, who occasionally produced sharp bounce and turn.

Patterson and Gilkes batted cautiously after the resumption knowing that wickets fell in clumps at the same stage on the previous day. The surface appeared to be flattening and an increasingly confident Patterson started to trust driving as he reached his half-century off his 156th delivery with a lovely stroke through the covers.

The milestone - rare in recent times at the WACA - received strong applause from his team-mates in the terraces, notably Sam Konstas who earlier in the day's play had been mobbed by kids desperate for selfies.

WA looked out of answers until the 93-run partnership - lasting over 41 overs - was broken seemingly out of nowhere. Gilkes, who earlier had almost been run out, turned slowly on the second run and was short of his ground after a brilliant throw from Jayden Goodwin at fine leg was collected at the stumps by wicketkeeper Joel Curtis.

Philippe's run-a-ball 26 ended when the towering Gannon showcased his athleticism with his latest brilliant catch at gully. But WA's bid to wrap up the innings was thwarted by Edwards as NSW batted through the day's play against the odds.